Case formulation involves the gathering of information regarding factors that may be relevant to treatment planning, and formulating a hypothesis as to how these factors fit together to form the current presentation of the client’s symptoms [264, 265]. The primary goal of AOD treatment services is to address clients’ AOD use. However, in order to do so effectively, AOD workers must take into account the broad range of issues that clients present with. As discussed in Chapter A2, clients of AOD treatment services, and those with comorbid conditions in particular, often have a variety of other medical, family, and social problems (e.g., housing, employment, welfare, or legal problems). These problems may be the product of the client’s AOD and mental health conditions, or they may be contributing to the client’s AOD and mental health conditions, or both. According to stress-vulnerability models (e.g., Zubin and Spring ), the likelihood of developing a mental health condition is influenced by the interaction of these biological, psychological, and social factors. These factors also affect a person’s ability to recover from these symptoms and the potential for relapse.
After developing a case formulation, the AOD worker should be aware of:
- What problems exist, how they developed, and how they are maintained.
- All aspects of the client’s presentation, current situation, and the interaction between these different factors and problems.
This information is the first step to devising (and later revising) the client’s treatment plan. There is no standardised approach to case formulation , but it is crucial that a range of different dimensions be considered, including history of present illness, AOD use history (amount and frequency, presence of disorder), physical/medical conditions, mental state, psychiatric history, trauma history, suicidal or violent thoughts, readiness to change, family history, criminal history, and social and cultural issues. Consideration also needs to be given to the client’s age, sex, sexual orientation, ethnicity, spirituality, socioeconomic status, and cognitive abilities.
Given the high rates of co-occurring mental health conditions among clients of AOD treatment services, it is essential that routine screening and assessment be undertaken for these conditions as part of case formulation. Screening is the initial step in the process of identifying possible cases of co-occurring mental health conditions . This process is not diagnostic (i.e., it cannot establish whether a disorder actually exists); rather, it identifies the presence of symptoms that may indicate the presence of a disorder. Thus, screening helps to identify individuals whose mental health requires further investigation by a professional trained and qualified in diagnosing mental health disorders (e.g., registered or clinical psychologists, or psychiatrists).
The potential clinical issues that these conditions can present suggest that screening for co-occurring mental health conditions should always be completed in the initial phases of AOD treatment. Early identification allows for early intervention, which may lead to better prognosis, more comprehensive treatment, and the prevention of secondary disorders [261, 262, 269].
Diagnostic assessment should ideally occur subsequent to a period of abstinence [270, 271], or at least when the person is not intoxicated or withdrawing. While the length of this period is not well established, a stabilisation period of between two to four weeks is recommended . A lengthier period of abstinence is recommended for longer-acting drugs, such as methadone and diazepam, before a diagnosis can be made with any confidence, whereas shorter-acting drugs such as cocaine and alcohol require a shorter period of abstinence . If symptoms persist after this period, they can be viewed as independent rather than AOD-induced. In practice, however, such a period of abstinence is rarely afforded in AOD treatment settings and, therefore, to avoid possible misdiagnosis, it has been recommended that multiple assessments be conducted over time [80, 94, 273]. This process allows the AOD worker to formulate a hypothesis concerning the client’s individual case and to constantly modify this formulation, allowing for greater accuracy and flexibility in assessment.
Screening forms the first part of the assessment process. Unlike screening, assessment is a process rather than a one-off event, which involves the ongoing monitoring of clients’ mental health symptoms. Ongoing assessment is important because clients’ mental health symptoms may change throughout treatment. For example, a person may present with symptoms of anxiety and/or depression upon treatment entry; however, these symptoms may subside with abstinence. Alternatively, a person may enter treatment with no mental health symptoms, but symptoms may develop after a period of reduced use or abstinence, particularly if the person has been using substances to self-medicate these symptoms.
Groth-Marnat  suggests that a combination of both informal and standardised assessment techniques is the best way to develop a case formulation. Figure 10 depicts how these techniques work together. In addition to these assessments, with the client’s consent, it may be useful to talk with family members, friends, or carers; they can provide invaluable information regarding the client’s condition which the client may not recognise or may not want to divulge (see Chapter A3) .